First off, understand that so long as the transmitter and receiver are on the same frequency, the basic function of the system isn't actually impacted by whether the frequency is "local" or not.

So the issue isn't "will my gear work." Given proper functioning gear - it will certainly work just fine anywhere the two units are near enough each other for the receiver to acquire the transmitters matching signal.

The issue in travel is whether or not the frequency band needed by your gear is already in use by other RF generating equipment.

With low power gear like wireless mic rigs, you're not putting out a very big signal in the great scheme of things. So the chance that you'll screw something up for someone else is typically very small. (Bets are off if you're in a pack of 20 news camera operators ALL of whom are trying to use similar wireless sound devices, so if that's on your agenda, this IS a big deal for you and keep researching to get a better chance for success!)

But as a single user in limited area n well away from other users, your chances for success will be very, very good.

If the recording situation is critical and you can't fail, the best bet is to get a "frequency agile" pair of transmitter receivers so you can search for clean channels at your location. Another reasonable approach is to take one unit in the VHF band, and one in the UHF band, and therefore have a fallback if one of the frequencies is problematic.

It all comes down to how lucky you feel, but the risk actually isn't all that big that you'll have any problems in a temporary - limited area - low power wireless use situation.

Hope that helps.

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